Door and door jamb mortising means and method



DOOR AND DOOR JAMB MORTISING MEANS AND METHOD Filed Jan. 23, 1956 P. R. GRAHAM Oct. 7, 1958 2 Sheets-Sheet 1 m mm m6 R m D IITTORNEY as as Get. 7, 1958 P. R. GRAHAM 2,854,761

DOOR AND DOOR JAMB MORTISING MEANS AND METHOD Filed Jan. 23. 1956 I 2 Sheets-Sheet 2 22 as as 48 89 a2 34- i '5 4? W a5 6 20 35 AW 9 4 I8 94 I5 17 T TORNE Y United States Patent O DOOR AND DOOR JAMB MORTISING MEANS AND METHOD This invention relates to door and door jamb mortising means and method and the present invention is well adapted for use in connection with door and door jamb mortising means of the type disclosed in my Patent No. 2,709,855, issued June 7, 1955. However this invention may be used independently of the disclosures of my said prior patent.

An object of this invention is to provide improved methods of mechanically gauging the positions of mortise recesses in doors and door jambs and to provide improved devices for use either independently of or in connection with apparatus of the type disclosed in my above identified patent to increase accuracy in instances where the mortising is done with suflicient precision so that the mortised doors and door jambs do not have to be individually fitted to each other but are interchangeable, thus saving time and expense in cutting and fitting at the locations where the doors are hung.

In hanging doors from door jambs in which the doors and door jambs are both mortised to receive butt type hinges it is desirable to accurately position the hinges so that each door, when hung and in a closed position, will have a predetermined clearance between the stop shoulder of the jamb and the adjacent face of the door. It is also desirable'to make provision for this clearance by accurately mortising both the doors and the door jambs so that the mortise recesses will serve as positioning means for the hinges and will save time in installing the hinges and insure a high degree of accuracy in positioning the hinges and provide proper clearance between the doors and the stop members of the jambs. Doors are rated in accordance with their thickness. Two standard sizes of doors commonly used in residential construction are known to the trade as one and three-fourths inch or outside doors and one and three-eighths inch or inside doors. However there is considerable variation in the actual thickness of doors having the same thickness rating, some being oversize and others being undersize. To insure the clearance accuracy and ease of hinge installation hereinbefore mentioned, in doors of varying thickness, it is necessary to gauge the width of the mortise recesses in the doors from the sides of the doors which will be adjacent to the stop members of the door jambs after the doors are hung. It is further necessary to gauge the width of the mortise recesses in the jambs, the dimensions of which may also vary, from the stop shoulders rather than from the edges of the jambs.

The present invention provides means for thus gauging the mortise recesses in both the doors and the door jambs so that on jambs the distance from the back edges of the mortise recesses to the adjacent face of the stops will always be uniform and on doors the distance from the back edge of the mortise recesses to the face of the doors adjacent to the stop members on the jambs will always be uniform and will be a predetermined amount less than the corresponding distance on the jambs to thereby provide the desired clearance.

Other objects of this invention are to provide a jig ice plate attachment of novel and efficient construction and a router gauge of novel and efiicient construction, both especially well adapted to the mortising of two pieces of work at one mortising operation and both capable of being used in the mortising of a single piece of work.

Other objects of this invention will be apparent from the following description taken in connection with the accompanying drawings.

In the drawings- Figure l is a fragmentary plan view of a mortising jig in connection with which this invention is used.

Fig. 2 is a view in cross section taken substantially on broken line 22 of Fig. l and on a larger scale than Fig. l and showing the mortising jig applied to two doors.

Fig. 3 is a detached perspective view of an insert plate used in connection with the mortising jig shown in Figs.

1 and 2.

Fig. 4 is a fragmentary sectional view showing a hinged together-door and door jamb having a proper clearance resulting from the use of this invention in mortising the same.

Fig. 5 is a plan view of a jig plate attachment constructed in accordance with this invention, showing the same attached to a fragment of a jig plate of the type shown in Fig. 1.

Fig. 6 is an edge view of this attachment looking in the direction of broken line 6-6 of Fig. 5.

Fig. 7 is a view partly in section and partly in elevation taken substantially on broken line 7--7 of Fig. 5.

Fig. 8 is a cross sectional view of said attachment taken substantially on broken line 88 of Fig. 5 and showing the same attached to the jig plate of Figs. 1 and 2 and applied to the edges of two doors and further showing parts of a router tool and gauge used with this attachment to simultaneously make mortise recesses in the two doors at one mortising operation.

Fig. 9 is a detached perspective view of one of the gauge members of the attachment.

Fig. 10 is a detached view in elevation of a router gauge used in connection with the attachment shown in Figs. 5 to 9 inclusive and forming part of this invention.

Fig. 11 is a sectional view, with parts in plan, taken substantially on broken line 1111 of Fig. 10.

Fig. 12 is a sectional view illustrating the use of the gauge shown in Figs. 10 and 11 in mortising door jambs for the reception of butt type hinges.

Fig. 13 is a sectional view similar to Fig. 12 showing this gauge applied to the mortising of door jambs for the reception of strike plates for locks.

Fig. 14 is a plan view showing an insert plate of a type which can be used in mortising door jambs to receive strike plates for locks and showing a fragment of a jig plate holding the insert plate and further showing fragments of two door jambs.

Like reference numerals refer to like parts throughout the several views.

Figs. 1, 2 and 3 show a door and door jamb mortising means of a type disclosed in my hereinbefore identified prior patent and with which my present invention is Well adapted to be used. It will be understood however that my present invention may be used independently of the mechanism shown in Figs. 1, 2 and 3. Said Figs. 1, 2 and 3 show a relatively long narrow flat jig plate 15 preferably made up of a plurality of sections which are longitudially adjustable relative to each other to take care of doors and door jambs of different lengths and are provided with stop means for engaging both ends of the doors or door jambs to which the jig plate is applied, all as fully described in my prior patent above identified. Openings 16 are provided at intervals in jig plate 15.

An insert plate 17, Figs. 1 and 3, is adapted to be inserted in and preferably removably secured within each assarct Queu n 1. lash in ert 121 91 a a r c an a m tise opening 18 of proper size and correctly positioned to receive and guide a mortising tool, such as a router h t- Eaqhins -t P at ha a d e P a 9 se r the e qansl ext n i lo ud 1 he b m Side of the insert plate medially thereof across the mortise opening 18. Each divider plate is positioned in a plane perpendicular to the insert plate and is of drop center or shallow .JJ shape in side elevation withtitsend portions rigidly attached --to the -insert plate. The downwardly arched or drop center portion of each diyider plate 19 spans the mortise opening 18 of its insert plate 17 and provides clearance for the peration of a mortising tool across the top edge 'of theldrop center portion of said div de plat it: simultane usly mc s two doors We dee i mbs- Each jig plate has .a plurality of work rest bars 20 welded or ,otherwise rigidlysecured to its bottom side at suitable intervals, said ,bars 20 being adapted to rest on the work pieces being mortised and supporting the jig plate in spaced relation from the work pieces.

Preferably .at least two sets of work clamping devices, only ,one set of which isshown in Figs. 1 and 2, are provided in connection with each jig plate to clamp the jig plate to the work. Each work clamping device comprises two-side by side transversely positioned clamp bars 21 and 22 extending across the top .ofthe jig plate '15 and slidably connected therewith by two keeper members 23. Opposite end parts of the :bars 21 and 22 overhang opposite edges of the jig plate and each of said overhanging bar portions is bent to provide a downwardly ofl set vertical part 24 and a horizontal part 25 and avertical work piece engaging part 26.

The bar 21 of each set has one end portion of a lever arm 27 connected therewith by a pivot screw 28. The screw 28 is selectively insertable into different threaded holes 29 in the bar 21 for adjustment purposes. The other -=bar 22,of each .set is pivotally connected with the lever arm 27 by a link 30. A shouldered and threaded screw 31 insertable into different threaded holes 32 of bar 22 provides an adjustable connection of link with the bar 22. The lever arm 27 is movable into engage ment with a fixed stop 33, which is rigidly secured to an adjacent part of the jig plate 15, to spread the work engaging means ,of the bars 21 and 22 apart. Said bars 21 and 22 are yieldingly urged into clamping engagement with the work by a tension spring '34 which has its two end portions connected respectively with plates 35 which are secured to the vertical parts 24 of the respective bars :21 and 22.

:When the clamp means above described is to be used for holding doors 36 then a separable door clamp 37 is secured to the part 25 of each clamp bar 21 and 22 by means suchas a set screw 38. Each door clamp 37 has a door engaging tip 39. The use of the door clamp 37 is optional when the jig plate 15 is being used on doors in connection with my attachment plates, as hereinafter explained. Also this clamp 37 is removed and the elements 26 are used as clamp jaws when the jig plate 15 is being used on door jambs, Figs. 12 and 13.

Ifv the devices shown in Figs. 1,2 and 3 are used without my attachment means in routing mortise recesses 41 in .theedges of doors 36 the lateral edge walls of the insert plate openings 18 are necessarily used in gauging the width of the mortise recesses and determining the positions of-the back edges of said recesses. This, in effect, gauges the mortise recesses from the door faces 36a which contact the divider plates 19 and variations in the thick; ness of the doors causes variations in the distances of the mortise recesses from the door faces 36b. Also the apparatus of Figs. '1 to 3, when used in mortising, door jambs, will gauge the mortise recesses fromthe edges of the door jambs and will not maintain a constant distance between the back edges of the mortise stopfaces'45 of the jain'b'sl In hanging doors from door jambs using butt type hinges, Fig. 4, it is desirable to position the hinges so that a clearance of about one sixteenth of an inch is provided between the face 36b of the door and the adjacent stop shoulder 45 of the jamb in closed door position. This is facilitated by having the mortise recesses 41 and 42 accurately positioned so that when parts of the hinge 46 abut the back wall of the mortiserecesses this desired clearance will he obtained.

In using the apparatus of Figs. 1, 2 and 3 the parts to be mortised are clamped against the divider plate 19, while the base 47 of arouter used in the work rests on the jig plate 15 and is moved thereover and the tool 48 of the router extends through the opening 18 in insert plate 17 and engages the work. Thus the edges'around the opening .18 in insert plate 17 are used to guide and limit movement oftherouter tool 48 and mortise recesses of apredetermined width, measured from thesurface of the work whichis clamped against the divider plate, are provided. This, in effect gauges the width of the mortise recesses from the divider plate contacting surfaces of the doors and door jambs. However where new doorsof a standard size vary substantially in thickness and where the transverse dimensions of jambs made for said doors may ,vary, the desired clearance between the face 45 of thedoor jamb stopand the adjacent face 36b of the door can best be insured by gauging the mortise recess 41 in the .door :from .the doorzface 36badjacent the back edge of said mortise recess and the mortise recess .42 in the jamb from the face 45 of the stop member 44 of the jamb.

Figs. 5 to 11 .show apparatus which can be applied to the jig mechanism disclosed in Figs. 1 to 3 and used to gauge the width of the mortise recess 41 in a door so as to insure proper .clearancebetween the door and the stop shoulder 45.0f1a door jamb40, as illustrated in Fig. 4. This apparatus comprises a .jig plate attachment, shown in Figs. 5 to 9 and a gauge used in connection with this attachmeugshown'in Figs. 18, 10.and.11.

This jig plate attachment, Figs. 5 to .9, comprises a plate 50 having a large rectangular mortise opening 51 therein and provided on its upper side with means for correctly positioning it against the under side of the jig plate 15 and securing itto said jig plate. The positioning means includes three blocks 52, 53 and 54 rigid with three corner portions of the plate .50 and a stud screw 55 rigid with the fourth corner portion of said plate 50. The holding or attaching means includes the set screw 55 and another set screw .56 in the block 54, and two L- shaped latch members5=7 and 58 pivotally mounted on the respective .blocks 5 2 and 53. When the plate 50 is applied to the under side of the jig plate 15 the heads of the two set screws 55 and 56 hook over one edge of said jig plate 15 and the latch members 57 and 58 are releasably engaged with the other edge portion of said jig plate.

The attachment plate-50 carries at least one and preferably two gauge members 60 and 61, at least one of which is movable toward and away from the other and these two gauge members also function as stop means and door clamping means. Preferably each gauge member 60 and'61 is of approximately T-shaped cross section and comprises a wide flat plate part 62 .as positioned against the bottom side of the plate 50 and an edge part formed of two perpendicular flanges 63 and 6 4. The upper flange 63 operates in the plate opening 51 and the lower-flange 6 4 extends downwardly below the plane of part 62. Door contacting means herein shown as 'a'relatively thin rib orstrip 59 isrigid with the face of the downwardly extending flange 64 of each gauge member and extends lengthwise along the lower edge of each flange .64. The thickness of contact member 59,.deterrecesses and the adjacent mines the clearance provided between door surface 36b and adjacent stop surface 45, as hereinafter explained.

Each plate part 62 has two inclined parallel slots 65. A screw 66 extends through each slot 65 and is threaded into plate 50 and preferably a flat metal strip 67 is provided between the heads of each pair of screws and the adjacent surface of the plate part 62. Usually the screws 66 are not clamped tightly against the strips 67 and thus each gauge member 61 and 60 is supported for diagonal movement relative to plate 50. Gauge members 60 and 61 are respectively connected by link members 68 and 69 with a lever 70. The lever 70 is connected with the plate 50 by a pivot pin 71 which is rigid with plate 50 and extends through a slot 72 in the lever 70. The pin 71 supports the lever 70 against endwise movement and yet allows enough floating movement of the lever 70 so that gauge members 60 and 61 are self adjusting to work pieces or doors they engage. Two tension springs 73 and 74 work in unison in yieldingly holding the two gauge members 60 and 61 in engagement with doors 36. Both of these springs tend to move the lever 70 clockwise from the position in which it is shown in Fig. 5. The tension spring 73, Figs. 5 and 7, has one end connected with a pivot member 75 by which the forward end of a link 68 is attached to gauge member 60 and its other end connected by a pin 76 with the plate 50. The spring 74 has one end connected by a pin 77 with one of the screws 66, which is rigid with plate 50, and the other end connected by a pin 78 with the lever 70. Thus both springs 73 and 74 tend to move the gauge member 60 to the right and the gauge member 61 to the left, as respects the showing in Fig. 5. For instance these springs can move gauge members 68 and 61 into positions indicated by dot and dash lines in Fig. 5. If desired one of the gauge members 60 or 61 may be fixedly clamped by tightening bolts 66, as will be described hereinafter.

The lever 70 is held in the retracted position in which it is shown in Figs. 5, 6 and 7 by a latch member 88 which is connected by a pivot 81 with the plate 50. A pin 82 operates in a slot 83 in the latch member 80 in limiting downward movement of the hooked end of latch member 80 and permitting said member 80 to be lifted to release lever 70. Latch member 80 will automatically engage with lever 70 when said lever is moved from a released position back to the retracted position in which it is shown in Figs. 5, 6 and 7.

A gauge of the form shown in Figs. 8 and 10 to 13 is secured to the base 47 of a router. This gauge is used in connection with the attachment disclosed in Figs. 5 to 9 in mortising doors and is used in mortising door jambs, as shown in Figs. 12 to 14 and hereinafter described. This gauge comprises a tubular shank 85 having an axial passageway 86 for the router tool 48 and having on its upper end a router base attachment flange 88 adapted to be removably secured as by screws 89 to the router base 47. Router base 47 is of conventional construction. A gauge member is rigid with the lower end of the shank 85. This gauge member comprises two oppositely positioned gauge elements including contact surfaces 91 disposed at a substantial distance from the axis of the shank 85 and two other oppositely positioned gauge elements including contact surfaces 92 disposed at lesser distances than the surfaces 91 from the axis of the shank 85. The two gauge elements with contact surfaces 91 are duplicates and the other two gauge elements with contact surfaces 92 are likewise duplicates. Thus the mortising of two doors or two door jambs at one mortising operation is facilitated but one door or one jamb at a time can be mortised if desired. Doors of difierent standard thickness ratings require gauges of different sizes and each gauge takes care of all hinge and strike plate mortising in doors and-door jambs of one standard thickness rating. The outer circumferential wall of the shank 85 is used to gauge the 6 length of all mortise recesses for both hinges and strike plates but the back walls of all of the mortise recesses are gauged by one or the other of the gauge parts 91 or 92.

In mortisin doors an attachment of the type shown in Figs. 5 to 9 is applied to the jig plate 15 under each one of the insert plates 17 where mortising is to be done. The insert plates 17 have the mortise openings 18 through which the work is done and said plates 17 also carry the divider plates 19 which insure proper relative positioning of the doors 36 and jig plate 17 with its attachments. This positioning is assured regardless of whether the jig plate, with attachments is attached to two work pieces or to one work piece since the divider plate 19 is rigid with the jig plate 15 and each work piece is independently clamped. At the time the jig plate 15, with attachments thereon, is brought into contact with the doors the lever 70 is latched in the retracted position in which it is shown in Figs. 5 and 6 and the gauge members 60 and 61 are thus supported in spread apart relation so as to receive the doors therebetween. Then the lever 70 is released and the springs 73 and 74 move the gauge members inwardly and press the gauge strips or ribs 59 against the doors firmly enough so that the gauge members 60 and 61 will not be moved outwardly later when they are contacted by the gauge means on the router. The inclined slots 65, operating on pins 66, also cooperate in preventing the gauge members 60 and 61 from being pushed outwardly.

In mortising doors to receive butt type hinges 46, the router, with gauge attached, is applied as shown in Fig. 8 with the longer gauge elements 91 positioned to contact the inner faces of the flanges 64, 63 above the gauge strips 59, which are pressed against the outer door faces 36b. Then when the mortising is done the distance from the door face 36b in contact with the gauge strip 59 to the back edge of the mortise recess 41 will be the same I in all instances and if the door jamb to which the door is hung is mortised as hereinafter described the clearance between the door and the adjacent stop shoulder of the door jamb, when the door is in closed position as shown in Fig. 4, will be equal to the thickness of the gauge strip 59.

If desired either of the gauge members 60 or 61 may be fixed instead of movable. This can be accomplished by first adjusting the gauge member to a' desired posi tion, then tightening the screws 66 sutficiently to clamp it in this position, and, if necessary, disconnecting at least one end of the link 68 or 69 which is attached to the clamped gauge member. If this is done both members 60 and 61 can still be used as gauges or either the fixed or the movable member can be used as a gauge with the other member functioning as a stop and clamping member.

The jig plate 15 shown in Figs. 1 to 3 serves as a support for two or more of the attachment plates 50 shown in Figs. 5 to 9 and properly positions these attachment plates longitudinally of doors of different lengths. Obviously these attachment plates 50 can be longitudinally positioned by other means and said attachment plates are self clamping onto the doors and can be used without the jig plate 15. When used with the jig plate 15 having insert plates 17 the end walls of the openings 18 in the insert plates gauge the lengths of the mortise openings in both doors and door jambs. The insert plate openings 18 are wide enough so that the lateral side walls of said openings are always clear of the router gauge shank 85. The work clamping devices 21, 22 etc. on the jig plate 15 can be used when working on doors but they can also be left inoperative and un-applied when working on doors because the gauge members 60 and 61 on the attachment plates will clamp the doors firmly enough to properly hold all parts in the correct position and insure accurate mortising. Preferably the divider plates 19 aroused buttheycanbe dispensed with in mortising both doors and door jigs.

The useof the gauge :shown in Figs. .10 and .11 in mortising doors to receive butt type hinges will not provide the correct clearance unless the same gauge is used in mortising the jambs'fromwhich .these' doors are hung. In mortising'door jambs the attachment shown in Figs. to 9 is omitted and the jig plate-15 is applied directly to the jambs, as shown in -Fig.' 12. --'I he.router,-of which base 47 forms a part, is positioned and held so that the longer gauge elements 91 engage the stop shoulders 45 of the jamh and the hack walls of the mortise recesses 42 are gauged from the stop shoulders 45. Then, if the back edges of thehinges 46, when installed,- are fitted closely against the back walls of the mortise recesses in both doors and jambs the doors will have the proper clearance from the stop shoulders 45 and this clearance will be equal to 'the thickness of the gauge ribs 59.

In using this attachment for doors, as shown in Fig. 8, each door 36 is independently clamped against the fixed divider plate 19. Consequently, if only one of said doors is present that door will be firmly clamped and can be mortised accurately. Similarly one .door jamb 48, as shownin Figs. 12 and 13, can be clamped and held and mortised if the other jamb is not present. Also because the back edges of the mortise recesses are gauged from the door surfaces 3612 instead of from the door surfaces 36a, in mortising doors, the divider plate 19 can be omitted and the two doors clamped face to face against each other and accurately mortised in that way.' Similar- 13/, when the mortises 42 in door jambs are gauged from the stop surfaces 45 the divider plate 19 can be omitted a'ndthe two jambs clampedtogether edge to edge and accurately mortised. If the divider platei's not used and only one door or one jamb is to be mortised then a piece of scrap material of proper dimensions can be used in place of the missing door or door jamb' andthe mortising can be done. i a

Figs. 13 and 14 illustrate the use of my router gaugefor forming in door jambs 410 mortise recesses 93 .to receive strike plates of locks. These strike plate mortise recesses are usually of difierent shape and dimensions than the hinge receiving recesses. In forming the strike plate mortise recess 93an insert plate .94 having an opening 95 of shape and dimensions partly determined by the shape and dimensions of the mortise recess desired is inserted in a jig plate 15' which is similar to the jig plate 15 and which will correctly position the insert plate 94 lengthwise of thedoor for the'purpose of strike plate mortising, it being understoodlthat the strike plate mortise in a door jamb is longitudinally offset fromthe hinge mortises in the same jamb. "Strike plates for locks are standardized to provide correct installation when they are positioned with the back edges of the strike plates at a predetermined distance from the adjacent stop shoulders 45 of the door jambs. The'opening 95 in the plate 94 is large enough so that the outside lateral walls 96 of said recess 95 are clear of the router gauge shank 85 and these lateral walls 96 are not used as gauge surfaces. All of the other internal walls bounding opening 95 are used as gauge surfaces to be engaged by router shank-'85.

The router is applied as shown in Fig. 13 with shorter gauge elements 92 positioned so they will engage with and be guided by the stop shoulders 45 of the jambs.

Thus the back edge of the mortise, recess \93 will be gauged from the adjacent stop shoulder-45 and proper positioning of the strike plate will be insured. Mortise recesses made in this manner with insert plate 194 may have the shape shown by dot and dash lines 95a in-Fig. 14.

Obviously changes in my invention maybe made within the scope of the following claims.

I claim: 9 i i 1. An attachment for a door mortising jig plate has at least one tool guiding opening comprising an athmen p e havin n p n center rs sisf n with the opening in the jig plate when the attachmt nt plate is attached to the jig plate; and two spaced'apartlaterally positioned gauge members movably ca rr ied by said attachment plate, each gauge member havingan inwardly facing flat gauge surface and having door-contacting means protruding inwardly beyond the plane of said gauge surface adapted to position the gauge member with the gauge surface thereof inparallel back set relation to the plane of the adjacent face of thedoor.

2. The apparatus as claimed in claim 1 in which springs are connected with the gauge members yieldingly urging said gauge members toward each other and a gauge member retracting lever is connected with said gauge members providing movement apart of said gauge members.

3. An attachment for a door mortising jig plate which has a tool guiding mortise opening and has a fixedly attached drop center divider plate extending longitudinally of the lower side of the jigplate across theopening, comprising an attachment plate having an ,open center regis tering with the opening in the jig plate and providing clearance for the divider plate when the attachment plate is supported by the jig plate in contact therewith; two spaced apart opposed laterally positioned gauge members movably carried by said attachment plate, each gauge member having an inwardly facing gauge contacting surface andhaving door engaging means protruding inwardly beyond the plane of said surface; springs connected with said gaugemembers yieldinglyurging said gauge members toward each other; and a gauge mernber retracting lever connected with said gauge members.

4; An attachment for a door mortising jig plate which has a tool guiding mortise opening therein and. has a fixedly attached drop center divider plate extending longitudinally of the lower side of .the jig plateacross the tool guiding mortise opening, comprising a flat attachment plate having an opening of larger sizejthan the tool guiding mortise opening of the jig plate registering with the opening in the jig plate'and providing'clearance for the divider plate when the attachment plate is supported against the lower side of the jig plate; two gauge members of T-shaped cross section each comprising a flat plate shaped part resting against the bottom side ofthe attachment plate and ahead flange positioned 'atJeast partly within the opening in the attachment plate, the head flange of each gauge member having an inwardly facing gauge contacting surface and having an inwardly protruding relatively thin door engaging member extending lengthwise thereof below said gauge contacting surface; springs interconnecting said gauge members and said attachment plate yieldingly urging said gauge members toward each other; and gauge member retracting lever means connected with said gauge members providing movement of said gauge members away from each other.

5. The apparatus as claimed in claim 4, in which diagonal slots are provided in the fiat plate shaped part of each gauge member and at least one mounting member having a head on its lower end extends through each diagonal slot and is rigid with said attachment plate, said diagonal slots resisting outward movement of said gauge members by pressure applied against the faces of the gauge members.

6. In door mortising. means, a jig plate which has tool guiding mortise openings therein and has a fixedly attached drop center divider plate extending across each tool guiding mortise opening below'the jig plate; anattachment plate having an open center registering with an opening in the jig plate and providing clearance for the divider plate when the attachment .platelis supported below the jig plate in contact therewith;twospacedapart laterally positioned gauge members .movably supported in opposed relationby said attachment plate, each gauge member having an inwardly facing flat gauge contacting surface and having a door engaging element protruding inwardly beyond the plane of said gauge contacting surface; and a router gauge adapted to be secured to the base of a router and directed downwardly through the openings in said jig plate and said attachment plate, said router gauge having two substantially oppositely positioned laterally projecting gauge member contacting elements on its lower end.

7. An attachment for a door mortising jig plate which has a tool guiding mortise opening therein and has a fixedly attached drop center divider plate extending longitudinally of the lower side thereof across the tool guiding mortise opening, comprising a flat attachment plate having an opening of larger size than the tool guiding mortise opening of the jig plate; means on said attachment plate adapted to removably secure the same against the lower side of the jig plate with the opening in the attachment plate adapted to register with the opening in the jig plate and the divider plate adapted to extend downwardly through the opening in the attachment plate; two gauge members of T-shaped cross section each comprising a flat part resting against the bottom side of the attachment plate and a head flange adapted to be positioned partly within the opening in the jig plate and partly within the opening in the attachment plate, the head flange of each gauge member having an outwardly facing gauge contacting surface and having a relatively thin door engaging member protruding from and extending lengthwise thereof below the gauge contacting surface and positioned to engage the face of a door and maintain the gauge contacting surface in slightly back set relation to the face of the door, the flat part of each gauge member having at least two inclined parallel spaced apart slots; a pin extending through each slot and rigid with the attachment plate, said pins cooperating with the walls of said slots in moving said gauge members transversely toward and away from each other in response to movement of said gauge members longitudinally of said attachment plate and in resisting outward movement of said gauge members by direct transverse pressure against the gauge contacting surfaces thereof; a lever extending crosswise of one end portion of said attachment plate, said lever having a transverse slot positioned approximately mid way of the width of the attachment plate; a pivot pin rigid with the attachment plate and extending through the slot in said lever loosely pivoting said lever on said attachment plate; two links connecting the respective gauge members with said lever at opposite sides of said pivot pin whereby pivotal movement of said lever will move said gauge members; and spring means interconnecting said gauge members and said lever yieldingly urging said gauge members toward each other, said gauge members being moved apart by movement of the lever counter to the force exerted by said spring means.

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